/*
 *   Copyright 2012, Thomas Kerber
 *
 *   Licensed under the Apache License, Version 2.0 (the "License");
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *   limitations under the License.
 */
package milk.jpatch.access;

import milk.jpatch.CPoolMap;
import milk.jpatch.Patch;

/**
 * Denotes a patch of a single flag.
 * @author Thomas Kerber
 * @version 1.0.0
 */
public class FlagPatch implements Patch<Integer>{
    
    private static final long serialVersionUID = 4383503994086980376L;
    
    /**
     * The position of the bit, counting from right. (rightmost is 0)
     */
    public final int pos;
    /**
     * Whether the bit should be switched on or off.
     */
    public final boolean on;
    
    /**
     * Creates a new flag patch.
     * @param pos The position of the flags in the flags.
     * @param on The value of the flag.
     */
    public FlagPatch(int pos, boolean on){
        this.pos = pos;
        this.on = on;
    }
    
    /**
     * Patches the flags.
     * @param flags The flags to patch.
     * @return The flags with the bit at "pos" having the value "on".
     */
    public int patch(int flags){
        int val = 1 << pos;
        if(on)
            return flags | val;
        else
            return flags ^ val;
    }
    
    @Override
    public final Integer patch(Integer flags, CPoolMap map){
        return patch(flags.intValue());
    }
    
}
